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Chapter 23
Nuclear Physics
Selected Isotope Masses Homework # 175
1 Hydrogen H 1 1.007825
Deuterium D 2 2.014102
Tritium T 3 3.016049
2 Helium He 3 3.016029
4 4.002602
3 Lithium Li 6 6.015121
7 7.016928
4 Beryllium Be 7 7.016928
9 9.012182
5 Boron B 10 10.012936
11 11.009305
6 Carbon C 11 11.011433
12 12.000000
13 13.003355
14 14.003242
7 Nitrogen N 13 13.005738
14 14.003074
15 15.000108
8 Oxygen O 15 15.003065
16 15.994915
18 17.999160
9 Fluorine F 19 18.998404
10 Neon Ne 20 19.992435
22 21.991383
11 Sodium Na 22 21.994434
23 22.989767
24 23.990961
12 Magnesium Mg 24 23.985042
13 Aluminum Al 27 26.981538
14 Silicon Si 28 27.976927
31 30.975362
15 Phosphorus P 31 30.973762
32 31.973908
16 Sulfur S 32 31.972071
35 34.969033
17 Chlorine Cl 35 34.968853
37 36.965903
18 Argon Ar 40 39.962384
19 Potassium K 39 38.963708
40 39.964000
20 Calcium Ca 40 39.962591
21 Scandium Sc 45 44.955911
22 Titanium Ti 48 47.947947
Atomic
Number
Z Element Symbol
Mass
Number
A
Atomic
Mass
Atomic
Mass
Mass
Number
ASymbolElement
Atomic
Number
Z
23 Vanadium V 51 50.943962
24 Chromium Cr 52 51.940511
25 Manganese Mn 55 54.938048
26 Iron Fe 56 55.934940
27 Cobalt Co 59 58.933198
60 59.933820
28 Nickel Ni 58 57.935346
60 59.930789
29 Copper Cu 63 62.929599
65 64.927791
30 Zinc Zn 64 63.929144
66 65.926035
31 Gallium Ga 69 68.925580
32 Germanium Ge 72 71.922079
74 73.921177
33 Arsenic As 75 74.921594
34 Selenium Se 80 79.916519
35 Bromine Br 79 78.918336
36 Krypton Kr 84 83.911508
37 Rubidium Rb 85 84.911793
38 Strontium Sr 86 85.909266
88 87.905618
90 89.907737
39 Yttrium Y 89 88.905847
40 Zirconium Zr 90 89.904702
41 Niobium Nb 93 92.906376
42 Molybdenum Mo 98 97.905407
43 Technetium Tc 98 97.907215
44 Ruthenium Ru 102 101.904348
45 Rhodium Rh 103 102.905502
46 Palladium Pd 106 105.903481
47 Silver Ag 107 106.905091
109 108.904754
48 Cadmium Cd 114 113.903359
49 Indium In 115 114.903876
50 Tin Sn 120 119.902197
51 Antimony Sb 121 120.903820
52 Tellurium Te 130 129.906228
53 Iodine I 127 126.904474
131 130.906111
Chapter 23
Nuclear Physics
Selected Isotope Masses Homework # 176
Atomic
Number
Z Element Symbol
Mass
Number
A
Atomic
Mass
Atomic
Mass
Mass
Number
ASymbolElement
Atomic
Number
Z
54 Xenon Xe 132 131.904141
136 135.90721
55 Cesium Cs 133 132.905436
56 Barium Ba 137 136.905816
138 137.905236
57 Lanthanum La 139 138.906346
58 Cerium Ce 140 139.905434
59 Praseodymium Pr 141 140.907647
60 Neodymium Nd 142 141.907718
61 Promethium Pm 145 144.912745
62 Samarium Sm 152 151.919728
63 Europium Eu 153 152.921226
64 Gadolinium Gd 158 157.924099
65 Terbium Tb 159 158.925344
66 Dysprosium Dy 164 163.929172
67 Holmium Ho 165 164.930320
68 Erbium Er 166 165.930292
69 Thulium Tm 169 168.934213
70 Ytterbium Yb 174 173.938861
71 Lutecium Lu 175 174.940772
72 Hafnium Hf 180 179.946547
73 Tantalum Ta 181 180.947993
74 Tungsten W 184 183.950929
75 Rhenium Re 187 186.955746
76 Osmium Os 191 190.960922
192 191.961468
77 Iridium Ir 191 190.960585
193 192.962916
78 Platinum Pt 195 194.964765
79 Gold Au 197 196.966543
80 Mercury Hg 199 198.968253
202 201.970617
81 Thallium Tl 205 204.974400
82 Lead Pb 206 205.974440
207 206.975871
208 207.976627
210 209.984163
211 210.988734
212 211.991872
214 213.999798
83 Bismuth Bi 209 208.980374
211 210.987254
84 Polonium Po 210 209.982848
214 213.995177
85 Astatine At 218 218.00868
86 Radon Rn 222 222.017571
87 Francium Fr 223 223.019733
88 Radium Ra 226 226.025402
89 Actinium Ac 227 227.027749
90 Thorium Th 228 228.028716
232 232.038051
91 Protactinium Pa 231 231.035880
92 Uranium U 232 232.037131
233 233.039630
235 235.043924
236 236.045562
238 238.050784
239 239.054289
93 Neptunium Np 239 239.052932
94 Plutonium Pu 239 239.052157
95 Amercium Am 243 243.061373
96 Curium Cm 245 245.065484
97 Berkelium Bk 247 247.07030
98 Californium Cf 249 249.074844
99 Einsteinium Es 254 254.08802
100 Fermium Fm 253 253.085174
101 Mendelevium Md 255 255.09107
102 Nobelium No 255 255.09324
103 Lawrencium Lr 257 257.0995
104 Rutherfordium Rf 261 261.1086
105 Dubnium Db 262 262.1138
106 Seaborgium Sg 263 263.1182
107 Bohrium Bh 262 262.1231
108 Hassium Hs 264 264.1285
109 Meitnerium Mt 266 266.1378
See the Table of "Selected Isotopes" on this first two pages of this chapter.
Nuclear StructureI
01. What is the rest energy of an � particle?
02. Convert the mass of a pi meson (139 MeV/c2) to atomic mass units.
II
03. What is the approximate radius of a 28
60 Ni nucleus?
04. What is the approximate value of A for a nucleus with a radius of 4.8 x 10-15 m?
05. How much energy must an � particle have to just barely "touch" the surface of a 92
238 U nucleus? [Hint: The �
particle must have enough (kinetic) energy to overcome the electrostatic potential energy that exists when the
two nuclei touch (radius of � particle plus radius of 92
238 U nucleus).]
Binding Energy & Nuclear ForcesI
06. Estimate the total binding energy of __________.
a.) 8
16 O b.) 16
35 S c.) 79
197 Au d.) 82
208 Pb
II
07. Calculate the total __________ for 4
9 Be.
a.) binding energy b.) binding energy per nucleon
08. What is the binding energy of the last neutron in a 7
14 N nucleus? [Hint: compare the mass of the 7
14 N to the
combined mass of 7
13 N + 0
1 n.]
09. How much energy would be required to remove a single neutron from a 7
14 N nucleus?
10. Show that the nucleus 4
8 Be (mass = 8.005308 u) is unstable to decay into two � particles.
11. Determine if 6
12 C is stable against decay into three � particles.
Chapter 23
Nuclear Physics
23.1 Nuclear Structure/Binding Energy and Nuclear Forces Homework # 177
ANSWERS: 01. 3728.4 MeV 02. 0.149 u 03. 4.70 x 10-15 m 04. 64 05. 28.4 MeV
06. a.) 127.6 MeV b.) 298.8 MeV c.) 1559.4 MeV d.) 1636.5 MeV 07. a.) 58.2 MeV b.) 6.46 MeV
08. 10.55 MeV 09. 10.55 MeV 10. � �m < m 8.005204 u < 8.005308 u2 particles Be48�
11. � �m > m 12.007806 u > 12.000000 u3 particles C612�
See the Table of "Selected Isotopes" on this first two pages of this chapter.
II
01. A 92
232 U nucleus emits an � particle with 5.32 MeV of kinetic energy.
a.) What is the daughter nucleus? b.) What is the approximate mass of the daughter nucleus?
02. State whether or not each of the following decays are possible. Provide energy calculations as support for your
statements.
a.) 92
236 U U + n92
235� b.) 8
16 O O + n8
15� c.) 11
23 Na Na + n11
22� d.) 82
211 Pb Pb + n82
210�
03. A nucleus of 6
12 C in an exited state emits a 4.4-MeV � ray as it drops to its ground state. What is the mass of the
excited carbon atom?
04. A 93
239 Np nucleus undergoes a �- decay.
a.) Write the complete equation for this decay.
b.) How much energy is released in this decay?
05. A 10
23 Ne (mass = 22.9945 u) undergoes a �- decay.
a.) Write the complete equation for this decay.
b.) What is the maximum kinetic energy of the emitted electron?
c.) What is the energy of the neutrino when the electron has its maximum energy?
d.) What is the minimum kinetic energy of the emitted electron?
e.) What is the energy of the neutrino when the electron has its minimum energy?
06. A 8
15 O undergoes a �+ decay.
a.) Write the complete equation for this decay.
b.) What is the maximum kinetic energy of the emitted proton?
c.) What is the energy of the neutrino when the proton has its maximum energy?
d.) What is the minimum kinetic energy of the emitted proton?
e.) What is the energy of the neutrino when the proton has its minimum energy?
07. Write the complete decay equation to describe a 36
81 Kr nucleus undergoing an electron capture decay.
08. In a decay series, a 92
235 U nuclide becomes 82
207 Pb. How many � and �- particles are emitted in this series?
Chapter 23
Nuclear Physics
23.2 Radioactivity-Alpha, Beta, and Gamma Decays Homework # 178
ANSWERS: 01. a.) 90
228 Th b.) 228.028818 u 02. a.) Impossible (-6.55 MeV) b.) Impossible (-15.66 MeV)
02. c.) Impossible (-12.4 MeV) d.) Impossible (-3.81 MeV) 03. 12.004724 u 04. b.) 0.722 MeV
05. b.) 4.41 MeV c.) 0 MeV d.) 0 MeV e.) 4.41 MeV
06. b.) 1.73 MeV c.) 0 MeV d.) 0 MeV e.) 1.73 MeV 08. 7 � decays, 4 �- decays
See the Table of "Selected Isotopes" on this first two pages of this chapter.
I
01. A sample of radioactive material produces 1560 decays per minute when first tested and 390 decays per minute
8.00 h later. What is its half-life?
02. What is the half-life of 11
24 Na if it has a decay constant of 1.287 x 10-5 s-1?
03. What is the decay constant of 92
235 U which has a half-life of 7.038 x 108 years?
04. What is the activity of a sample of 6
14 C that contains 8.45 x 1021 nuclei, if it has a half-life of 5730 years?
05. What fraction of a sample of 15
32 P, which has a half-life of about 14 days, will remain after 42 days?
06. How many nuclei of 49
115 In, which has a half life of 4.41 x 1014 years, are present in an iron ore if an activity
registers 3.40 decays per second?
II
07. A sample of 91
231 Pa (T = . x1
2
3 276 104 yr) contains 6.45 x 1016 nuclei.
a.) What is the decay constant? b.) What is the approximate number of decays/min?
08. The activity of a 3.85-�g sample of pure 14
31 Si (T = .1
2
157 3 minutes) is being monitored.
a.) How many nuclei are initially present?
b.) What is the initial activity?
c.) How many nuclei are present after 9.00 h?
d.) What is the activity after 9.00 h?
e.) How much time elapses from the start of monitoring until the activity drops to 1.00 % of the original sample?
f.) How much time elapses from the start of monitoring will the activity to drop to about 1 per second?
09. What is the activity of a 7.65-�g sample of pure 76
191 Os (T = . x1
2
133 106 s)?
10. The activity of a sample of 53
131 I (T = . x1
2
6 95 105 s) is 7.35 x 109 decays/sec. What is the mass of the sample?
11. The activity of a sample drops by a factor of 10 in 72.4 minutes.
a.) What is its half-life? b.) What might be the identity of this nuclide?
12. A 27.5-g sample of pure carbon is 1.10% 6
14 C (T =1
2
5730 yr). How many disintegrations occur each second?
13. A radioactive nuclide produces 6740 decays per minute initially, and 1400 decays per minute exactly 1 day later.
a.) What is its half-life? b.) What might be the identity of this nuclide?
Chapter 23
Nuclear Physics
23.3 Half-Life and Rate of Decay Homework # 179
ANSWERS: 01. 4.00 h 02. 5.39 x 104 s (15.0 h) 03. 3.12 x 10-17 s-104. 3.24 x 1010 decays/s 05. 1
8
06. 6.82 x 1022 nuclei 07. a.) 6.71 x 10-13 s-1 b.) 2.60 x 106 decays/min 08. a.) 7.48 x 1016 nuclei
08. b.) 5.50 x 1012 decays/s c.) 6.93 x 1015 nuclei d.) 5.09 x 1011 decays/s e.) 17.4 h f.) 111 h
09. 1.26 x 1010 decays/s 10. 1.60 �g 11. a.) 21.8 minutes b.) 87
223 Fr 12. 4.99 x 1010 decays/s
13. a.) 10.6 h b.) 82
212 Pb